Regenerative furnace and method of firing furnaces



June 2, 1925.

K 1 $ODERSTROM REGENERATIVE FURNACE AND METHOD OF FIRING FURNACES 3 Sheets-Sheet 1 Filed May 7 25, 1923 W/T/VESS:

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K. A. SODERSTROM v REGENERATIVE FURNACE AND METHOD OF FIRING FURNACES Filed Ma 23, 1923 3 Sheets-Sheet 2 W/BW A 77'0/P/VE K 3 Sheets-Sheet June 2, 1925.

K. A. SODERSTROM REGENERATIVE FURNACE AND METHOD OF FIRING FURNACES Filed May 23. 1923 \X L m a m.

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Patented 2, 192; v 1 5395879 UNITED: STATES PATENTLOFFICE'.

- REGENERATIVE uR wAcjnAND n'rHoD F FIRING FURNACES.

Application filed May 237 1923. Serial No. 640,822.

To all whom it may concern." companying drawings; it being premised, Be it known-that'I, KARL A. SoDERsTRoM, however, that various changes .may be made a citizen of the United-States, residing at ,inthe' details of construction'without de- 5 Philadelphia, county of Philad'elphiaQand.parting' from the spirit -andffscope of. my 6 State of Pennsylvaniaahav'e invented a new invention as definedinjthe a pended claims; and useful Improvement in Regenerative."li-Figi 1 is a vertical?"longitudinal section Furnaces and Methods of Firing Furnaces, through one form of furnace' -built in .ac j of which the following is a full, clear, and oordance with "my; invention; ;on.. the-line 60' exact description, reference being'had to 11 of Fig. 2. '3 f the accompanying drawings, which form- I Fig. 2 is ahoriz'ontalsection'on line2-+2 a part of this specification. of Fig. 1. J-

' 1 4' This invention relatesto an improvement .Fig. ;3 is a similar view on the line 3--3 V y 65 in open hearth regenerative furnaces and of- Fig. 1. the method of firing such furnaces. y "I-Fig. 4 is a vertical transverse section on; One of the objects of my. invention is line 4-4 of Fig. 1, looking toward. the to provide a furnace of'this type in which combustion chamber; I: 1 .j' the air for supporting combustion is heated' Fig. 5 is .awertical section on the line by direct contact with the outgoing pr'od- 55 of Fig. 2. 70

nets of combustion, and thereby partiallyl Fig. 6 is also a sectional view on the line' heating the air andieducing the tempera; H. of Fig. 1, looking towardfthe' flues ture of the waste gases. leading from the combustion ch mber, I

Another object-of my invention is'to ac.-- Referring to the accompanying drawings, celeratev the speed of the outgoing waste 10 designates the combustion chamber'above 75 gases by direct contact with the ingoing the hearth-.11 and below the roof 12. air, thus quickly drawing the spent gases cated between the roof 12 of the combus from the combustion chamber andthereby -tion chamber and the main roof 13 'is -a" increasing the. temperature of the hearth regenerator chamber. The 'regenerator or combustion chamber, an'dfas the {force chamber is divided. into twochambers 14- i k 'of the ingoing air is underfthedirect conand 15 by a central wall 16; while these" trol of the furnace man, the temperature chambers 14 and 15 are divided. by walls of the furnace can readily becont'r'olled. I 17 and- 18, respectively. Another object of my invention is torap- Between thewalls 17 and 18 and the sideidly extract heat from the roof of the walls of the furnace are flues19 and 2053 combustion chamber by theingoing air and respectively; for the outgoing gasesor prod-' thereby increase the life thereof and at the nets of combustion. The flue 19 communisame time increase the temperature of the cates with a downtake-flue'21, while the ingoing air. flue- '20 communicates with a similar flue A further obj utilize some of the waste products vof comthe transverse main or oiftake flue 23, which bustio ii -for atomizing and injecting the fuel may lead toa stack or some point where into the confiiustion chamber, which enables the heat in the products of combustion is me to prevent prematureignition and 'conutilized for heating purposes.

act of. my invention is to 22. The flues 21 and 22 communicate with trol subsequent combustion by reason of low- Located between the central wall '16 and ered oxygen content of the atomiz'ing agent. walls 17 and 18 are air passages 24 and 25', Another object of my invention is to prorespectively. which communicate with a vide means for varying the heating of the downwardly and reversely extending pas opposite sides of the hearthor combustion sage 26, the, mouth of which communicates chamber, so that the temperature ofthe with the combustionchamber 10. i

bath bn different sides of the hearth can Extending laterally from the flues 21 and 50 be controlled by the furnace'man. 22 and communicating with the combustion The precise nature of my invention. chamber 10 above passage 26ar epassages27 be best understood by reference to the ac- 'and 28. 29 and 30 are dampers-win passag 27 and 28, respectively, for controlling the flow through said passages, and 'located in flues 21 and 22 are baffles 31 and-'32,--respecit and extending downwardly in this space is a main fuel feedpipe 33, having branches" ,34 and extending into passages 27 and tively, for directinghsomeof the products of combustion from flues 21 and 22 into passages 27 and 28. The central wall 16 is chambered between airpassages-24 and 25.

28, respectively, 'and are arranged to feed powdered fuel to said "passages. .35 1s a control handle extending from adeflector The passages-26, 27 and 28 do not communicatedirectly with the plate in pipe 33 combustion chamber, but open into a con mon port 36, which is directly in communi- .cation with the front end of the combustion The rear end of the combustion chamber. 7 chamber 1s m communlcatlon Wltll two offtake flues 38 and '39, the upper ends; of

' 48 through pipe 49. The pipe 49 is providwhich communicate with what'I term the front end of the regenerator chamber above the rear end of the combustion chamber, and an arch-shaped water-cooled nose- 36 at the mouth of port 36. I

40 are doors closing clean-out openings communicating witlrfiues 38' andv .41 is a tap-out opening through one of.

the side walls of thefurnace, and 42 is' a runner for the metal extending from'said opening. The side walls of theifurnace are also provided with aplura lity of charging. and working openings 43'whi'ch are'provid ed with the usual closures.

44 and 45 are openings in'the' upper portions of the'frontiwalls of lines 38 and39, respectively. 1

46 and 47 are nozzles for directing the air for supporting combustion into the regenerator chamber through openings 44 and 45, and are supplied with air-by a blower ed with -a eflector plate having a handle 50, and is'arranged to equally dividethe air passing through pipe 49 to the nozzles, or to direct-more air to one nozzle than the other. i

\ The downtake portion of air passage 26 is provided with a removable hood 51. while the downtakes-21 and 22are provided with similar hoods 52. These hoods can readily be removed. sothat the passages can be quicklyccooled and provide ready access for cleaning and inspecting the various passages, while the/doors 40in 'flues-38'and 39 provide meansfor readily cooling saidpassages and for removing slag which has been carried over from the hearth. 7

Assuming thatthe furnace/is charged. and in operation, the firing is carried on in-the I following manner.

Pulverized coal or other fuel is fed in a continuous manner at a predetermined rate to pipe 33, from which it is fed to passages 27 and28, dampers 29 and 30 being open to the proper extent] J etsof air are delivered to therege nerator chamber from nozzles 46 and 47, the air from blower 48. being delivered at the proper speed to cause the air to enter openings '44 and 45 at the required velocity. v p I V The air jets. from nozzles 46 and 47 pass directly through the products of combustion yrising through flues .38 and 39 from the combustion chamber 10. These air jets are directed towel-(leach other and in a downward direction toward the roof'13, but do not meet each other, as the point at which they would meet is slightly beyond the front of wall 16. suction the-flow of the spent/gases or products of combustion from the combustion:

chamber in proportion to their velocity, which velocity is somewhat reduced by the passage of the streams of air through the spent gases. During the passage of these streams: of air through the rising spent gases, the temperature of the gases isre-.

duced while the streams of airwill be' raised in temperature .by radiation and convection.

As the velocity-0f the streams of air is very high, the streams will not be broken-up to any detrimentaljextent (for example, before These jets of air increase by r tionally carried by the, air streams through chambers 14 and 1 5 between the streams of air and the side walls of the furnace,1and

pass into flues 19 and 20 at a fairly high' velocity. These streams of spent gases pass from fiues 19 and 20 into the respective flues 21 and 22. These streams of spent gases in fines 21 and 22 are split upiby baflles 31 and 32. A port-ionof the stream in flue 21 is directed to passage 27 by bafi'ie 31, while a portion of the stream in flue 32 'is directed into flue 22 by baflle 32. I

The velocity of the streams of spent gases or products of combustion pass g through passages 27 and 28 is sufli'cient to atomizaand carry the fuel delivered thereto into the combustion chamber where it is thoroughly mixed withthe stream of air from passage 26 r As'the spent gases which carry the fuel into the combustion chamber and the fuel .do not form a combustible mixture, combustion does not take place until a mixture is formed with the air at' the entrance of combustion chamber 10, and combustion cannot take place in the fuel or air delivery ports. The remainderof the spent the temperature of the furnace can Y raised or lowered by varyingthe.velocity" of the air and the feed of the fueland the percentage of oxygen content" of" themix= gases passing down fiues 21 and 22 enters the flue 23, leading to a'sta'ckor -a Waste heat utilizing apparatus in which the remaining heat may be extracted and commercially used. i

If it is desired to apply-a greater heat to one side of the furnace than to the other,

the deflector" plates in air pipea9 and fuel pipe 33 are positioned to direct a greater' q amount of air and fuel to the side hich is to be heated to the greatest 'extentQ- It will also readily be understood tha ture.

As the roof 13 is of arc'uate form-over the uptake flues 38 and 39, as'well as over the r'egenerator chamber, the'heat therefrom will be radiated toward the jets of air first passing through the spent gases and then along the two streams of spent gases passing tofiflues 19 and 20.

The advantages of my inven nace of initial low cost, and in which-the ingoing air is partially heated by theout going spent gases, as well as afurnaeein which the roof of the combustion chamber is cooled by streams of air traveling at a high, velocity impinged against said roof;

thereby rapidly extracting the heat from said roof, wherebythe life ofthe furnace 1S greatly increased over that of a furnace over whose roof the air flows at a slow speed. 1

Another advantage results from the provision of a regenerative-furnace in which the air is heated without the use, of the usual checker work, or two setsiof chain;

bers with reversing valves, andfthereby eliminate thecost for cleaning thethecker-E work, cost of supplying'wa'terfor cooling the valves, as Well as the loss of heat carried off byithe-cooling water. 7 A further advantage results fromthe provision of a furnace in which the various fines and passages are relatively short,'so that I am enabled to provide hoods and doors at or near one'of the turns, wherebythe fines and passages can be quickly cooled, inspected, and cleaned.- V. A further advantage results from;- the provision of a furnace from which the speed of the outgoinggases from the combustion chamber is accelerated by suction generated by theingoing air,- so that the combustion chamber is maintained ata high temperature.

A still further advantage results from the provision of a furnace in which the fuel is carried into the combustion chamber by a non-combustible gas, so that ignition doesnot take place until the fuel has entered the tion" from the provislon of a.regenerative".fur-l combustion chamber and with a flame development under control.

Another advantage results from the provision of a furnace in which I am enabled .to carry out a method of firing in which the ingoing air is partially heated .by passing'thfrouglrthe outgoing spent gases, and

[that the stream of air will not be substanporting combustion in contact with the outgoing products of combustion to heat the air and propelling the air at such a'velocity tially, broken up, separating substantial-1y allof the stream'of air from the products ducting the separated stream of air into the combustion space of the, furnace, and forcing fuel into the combustion-space to form a combustible mixture with the air.

2. The method of firing'a furnace, comprising the step of forcing the air for supporting combustion in contact with the outf of combustion after contact therewith, c'ongoing products ofcombustion to heat the air and propelling the air at such a velocity that the stream of air will not be substantially broken up, separating substantially all of the stream of air from the products of combustion I after contact therewith, conducting the separated stream of air into the combustion space of the furnace, separating a portion of the products of combustion after separation from the air, conducting one portion of said products of combustion out of the furnace, and utilizing the re- ,m'ainder for forcing fuel into the com-' bustion space to form a combustible mixture with'the air. I f

3. The ,method' of firing a furnace, comprising the step of' carrying fuel into the combustion space of the furnace by a jet of non-combustible gas and simultaneously directing a current of air to" impinge on the roof-of the combustion space and thereafter to pass to the combustion space and commingle with the fuel to form a combus tible'mixture'whioh is ignited by the heat of the furnace.

4. The method of firing-a furnace, com prising the step of continuously separating from the outgoing products of combustion a portion thereof and continuously conveying fuel to the combustion space by the Separated portion of products of combustion and simultaneously and continuously directing a current of air to impinge on the roof of the combustion space and "there-- after commingle with the products of comwithin the combustion space of the furnace, and form a combusbustion a n d fuel tible mixture therewith.

5. A furnace having a combustion Space, an ofttake flue for the products ofcombustion leading therefrom, a regenerator chamber, means for directing a jet of air at a high velocity into the regenerator chamber in'contact with the products of combustion to heat the air, means in the regenerator for separating substantially all of the heated air from the products of combustion and 1 for conducting the air to the combustion space and means for injecting fuel into the combustion space. z v

6. A furnace having a combustlon space,

an olftake flue for the products ,of combustion leadingtherefrom, a regenerator chamher, means for directing a jet of air at a high velocity into the regenerator chamber-- in contact with the products, of combustion to heat the air, -means in theregenerator forseparating substantially all "of the heated air from the products of combustion and for conducting the air to the combustion space, means for conducting a portion of the products of combustion back to the combustion space, means for feeding fuel into the stream of products of combustion flowing to the combustion space, and means for directing a stream of a r into the stream of fuel and pr'oducts of combustion within the combustion. space.

- 7. A furnace having a combustion chamher, a regenerator. chamber, an ofi'take flue leading from the combustion chamber to the regenerator chamber, means for directing a jet of air into the regenerator chamber in contact With the gases passing from the combustion chamber to the regenerator chamber, an air flue leading from the re-' generatorchamber to the combustion chamher, an 'ofi'takeflue leading from the 'regenerator chamber. means .for directing some of the productsof combustion from the last flue-back to the combustion chain'- her, and means for feeding fuel into the stream of products of combustion-passing back to the combustion chamber. v

8. A' furnace having a combustion chamber,"a regenerator chamber above the combustion chamber, two flues at one end of the furnace for conducting theproducts of com bustion from the combustion chamber to the,

reg'enerator chamber, two air nozzles at the said endof the furnace for dlrecting blasts of air into the regenerator chamber through the flues,said nozzles being directed toward each other, a Wall in the regenerator chamber dividing the rear end of the regenerator major portion of the air from the pro the combustion space a passagercomm m icating" with each flue leadi'ng frointhe regenerator compartments and with thecombustion chamber, a battle n each fluefor directing a portion of the outgoing products of combustion into said last men-' tioned passages, and means for feeding fuel to-said'last jmentioned passage and into the paths of the streams of products of combustion flowing back to the combustion chamber.

9. A furnace having a. combustion space, an ofi'take for the'products of combustion, means for directing a jet of air at a high velocity into the offtake in contact with the products of combustion and thence intothe combustion space, means for diverting a part 7 of the productsof combustion from the off take and introducing them separately ,into the combustion space, and means forintro ducing fuel into the. diverted products of combustion before their bustion space. v

. 10. A furnace having a'combu sti'on space, an. ofi'take for the products of combustion,

entry into'the com,

means for directing a stream of air at high velocity in contact with theproducts ofcombustion, whereby the air is heated and a-portion of the products of combustion'diverted,

means for separating the major portion of the 'air from the diverted products of com- .bustion and leading the air and products of combustion separately into the combustion space, and means" for introducing finely divided fuel into the diverted products of combustion. I I v j 11. A furnace havin'g a combustion space, an ofl'take for the products of combustion at one end of-the combustion space, a passage connecting. the ofl'take with the other end of, the combustion space, meansfor introduc ing a stream of air athigh-velocity'through the ofi'take into said passage, whereby the air' is heatedand a portion of the productsof" combustion are diverted into the passage,"

means inth'e passage adjacent the opening into thecombustion space for dividin the ducts of combustion and causing-the air and prod nets of combustion to'enter the combus-' tion-space in separatestreams, andmeans for introducing finely divided fuel into the stream of products of combustion to be'carried into'the combustion space thereby. v

' 12. .A furnace'having a combustion space, v

anofi'ta-ke for the products of combustion at .one end, a passage leading affording communication between the ofitake and the comover the-top of bustion space, means for directing a stream of air at high velocity through the ofttake and into said passage in a direction to impinge on the top of said combustion space whereby said top is cooled, and means in said passage adjacent its opening into the combustion space adapted to divide the major portion of the air from the products of combustion and lead the air into the combustion space below the point of entry therein of the products of combustion, and means to introduce finely divided fuel into the separated products of combustion prior to the entry thereof into the combustion space.

13. A furnace having a combustion space, an ofl'take for the products of combustion atone end, a passage leading over the top of the combustion space and affording communication between the offtake and the combustion space, means for directing a stream of air at high velocity through the ofi take and into said passage in a direction to impinge on the top ofv said combustion space whereby said top is cooled, a partition dividing said passage into two parts adjacent its opening into said combustion space and an adjustable baffle adapted to effect a separation of the major portion of the air from the products of combustion and direct it to one side-of said partition and to direct the products of combustion to the other side of said partition, and means to introduce finely divided fuel into the separated products of combustion.

In testimony of which invention, I have hereunto set my hand, at Pittsburgh, Penna, on this 21st day of May, 1923.

KARL A. SODERSTROM. 

